The prevalence of obesity and being overweight is rapidly increasing worldwide. The development of foods with high satiating capacities and low energy densities may help to prevent weight gain and to stimulate weight loss. Consumption of food and drinks containing non-digestible carbohydrates instead of sugars induces a lower blood glucose rise after meals compared to sugar-containing food and drinks.
The most common carbohydrate in human diets is starch. This polysaccharide is produced by most green plants as an energy store. It is contained in large amounts in such staple foods as potatoes, wheat, maize, rice, and cassava. Various methods have been proposed for the chemical modification of starch and malto-oligosaccharides into non-digestible carbohydrates.
EP2427565 describes the use of a glucanotransferase enzyme of Lactobacillus reuteri 121 GTFB to convert starch into linear gluco-oligosaccharides containing relatively long isomalto-oligosaccharide side chains. Such materials are partially resistant to digestion and hence give less glucose production on consumption, contributing to the prevention of obesity and type II diabetes.
It has been observed that highly branched α-glucans can combine a reduced digestibility with a thickening effect triggered by the low pH conditions of the stomach. This thickening leads to feelings of satiety. The production of highly branched α-glucans from sucrose has been described, for example the synthesis of reuteran by the Lactobacillus reuteri 121 GTFA glucansucrase (Kralj et al., 2002).
It would be desirable to provide further means for the enzymatic modification of starch, starch derivatives and malto-oligosaccharides in order to change their functional properties and enhance their nutritional value. In particular it would be beneficial to provide enzymes to perform such modifications which are suitable for use in food manufacture and exhibit good enzyme activity and thermostability.
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